MELBOURNE (Reuters) - Novak Djokovic is "physically extraordinary" and can emulate Roger Federer by winning the Australian Open in his first tournament for six months, mentor Andre Agassi said on Friday.

The Serb arrived in Australia with question marks over his elbow injury and has played two rounds in Melbourne wearing a compression sleeve on his serving arm.

The 12-times grand slam champion has re-modelled his serving action to take the pressure off the joint but it held up during a four-set win over Gael Monfils in brutal heat on Thursday.

"If you haven't played for a long time, anything that isn't quite the centerpiece of your game, can go through a bit of a challenge," former world number one Agassi, who flew in to be in Djokovic's corner, told AAP on Friday.

"With a new service motion and the pressure and the big match and not playing in a while, that was the time for it to get tested and, getting through it, he'll be a lot better for it moving forward."

Djokovic had not played a competitive match for six months before his first round clash with American Donald Young and while that was a breeze, his clash with Monfils in 40 degrees heat proved to Agassi that the 30-year-old is battle ready.

"Recovery is not something I worry about with him," said Agassi, who added he is not working with Djokovic for 'personal gain'.

"Novak is physically extraordinary and he has a recovery ability that is unlike mine, probably just because the nature of how his body is made and how efficient he is.